I have a remington 700 sps ss in a 30-06. i went shooting and and was getting really good groups ( like 1/2") at 100 yards. Although i would shoot 3 shots , go check the target and then shoot again and my group would be in a different spot. This happened with a whole box. I was shooting from the same position on a rest, and shooting at the same target. Any suggestions to why this is happening let me know.

Barrel thickness makes a big difference as well in heating. My savage has a thicker barrel than my Ruger, and the ruger will be effected by heating pretty quickly. I usually can get 3 to 4 shots, but then I have to let it sit 10 to 15 mins to cool completely or it will become pretty erratic. My savage can handle less cooling time. I wouldn't rule out barrel heating. Try waiting until the barrel is completely cool between groups. If it still does it, you can rule out barrel heating and move on to the next possibility.

How different are the groups (1 inch, 4 inches, vertical, horizontal)? I could be a lot of things. Head position, wind, shadow, how you are holding the rifle, action screw tightness, scope mount tightness

Sounds like the scope mounts might be loose or have a broken screw or that the Bushnell has finally shot itself loose and the wires inside are moving around...............if all the stock screws on your gun are all "Snug".

Patterns normally only shift with a change of bullet weights or powder weight changes. If you are shooting the same load at 3 shot clusters with time for the barrel to cool down ,to the touch of your hand, there should be no noticable pattern ,point of aim, change, with proper breathing and trigger pull.